Gear pump or motor



Dec. 20, 1966 R. o. GORDON GEAR PUMP OR MOTOR SSheets-Sheet 1 FiledApril 26, 1965 I NVENTOR RICHARD O. GORDON ATTORNEY R- O. GORDON GEARPUMP 0R MOTOR Dec. 20, 1966 5 Sheets-Sheet 2 Filed April 26, 1965RICHARD O. GORDON I0 I BY ATTORNEY Dec. 20, 1966 R. o. GORDON GEAR PUMPOR MOTOR 5 Sheets$heet 5 Filed April 26. 1965 INVENTOR RICHARD o. GORDON(UM ATTORNEY United States Patent Filed Apr. 26, 1965, Ser. No. 450,9892 Claims. (Cl. 103-126) This invention relates to fluid displacementpumps and motors, and more particularly to improvements in pressureloaded gear pumps and motors.

Numerous problems have been encountered in the art of pressure loadedgear pumps and motors, particularly those designed for generatingrelatively high discharge pressures, operable at high mechanical andvolumetric efficiencies, and capable of high performance operation forrelatively long periods of time with minimum maintenance requirements,concerning which many and varied solutions have been previouslyproposed. A discussion of the prior art and the nature of such problemswhich have been encountered heretofore are reviewed in my Patent No.3,137,238, granted June 16, 1964.

The present invention is concerned with improvements in the structure ofsuch gear pumps and motors to provide a unit in which the sealing forceapplied inwardly at selected areas on the outer surfaces of the thrustplate sealing members is controlled to exceed the internal force exertedoutwardly at corresponding areas on the inner faces of the sealingmembers by substantially the same predetermined differential, thusproviding a positive sealing force which is substantially the samethroughout the area of the side surface of the adjacent gears. Briefly,this is accomplished by providing a plurality of movable wall or pistonmembers of preselected area and location which respond to the fluidpressures existent in different circumferentially spaced gear pocketareas for imposing on the outer surfaces of the thrust plate sealingmembers a force which is always proportional to the pressure in the gearpocket area to which the respective piston member responds.

It is therefore an object of the invention to provide an improved gearpump or motor construction in which accurate pressure gradientcompensation is realized by the use of control area variants whichprovide for a wide range of flexibility in design.

It is an additional object to provide an improved pump or motorconstruction utilizing localized internal gear pocket pressures toprovide the sealing forces in corresponding localized areas on the outersurface of the sealing member.

Another object of the invention is to provide a generally improved gearpump or motor construction.

Other objects, advantages, and features of the present invention willbecome apparent from the following detailed description thereof taken inconjunction with the drawings wherein:

FIGURE 1 is a longitudinal sectional view of a pressure loaded,intermeshing gear pump taken along the line 11 of FIG. 2 in accordancewith one embodiment of the present invention;

FIGURE 2 is an elevational end view of the pump taken from theright-hand side of FIG. 1 with the cover plate removed;

FIGURE 3 is an elevational end view of a modified form of the coverplate shown in FIGS 1 and 2;

FIGURE 4 is a partial sectional view of a modification of theconstruction shown in FIG. 1; and

FIGURE 5 is an elevational end view of another modified form of thecover plate.

Referring now in detail to FIG. 1 and 2, numeral denotes a suitablychambered gear pump housing in which are rotatably mounted a driven gear12 and an 3,292,551 Patented Dec. 20, 1966 ice intermeshing driving gear14. Driven gear 12 is supported on a shaft 16 journaled on its rightside in a roller bearing 18 and on its left side in a roller bearing 20;driving gear 14 has a splined shaft 22 journaled on its right side in aroller bearing 24 and intermediate its ends in a roller bearing 26. Theroller bearings 18, 20, 24 and 26 are mounted in annular recesses inthrust plate bushings 28, 30, 32 and 34, respectively, the verticallyrelated pairs of which bushing have flat mating surfaces at numerals 36and 38, respectively. Generally figure-8 shaped wear plates 40 and 42are interposed between the respective pairsof thrust plate bushings andthe opposite side'faces of the gears 12 and 14. All of the aforesaidparts of the pump structure are mounted within the figure-8 shaped gearchamber 44 formed by body housing 10. An opening 46 is formed in eachthrust plate bushing and wear plate of somewhat larger diameter than thedriving or driven shaft which passes therethrough to avoid wear and tofacilitate drainage of any leakage fluid from the gear chamber throughthe various bearings and back to the inlet of the pump as will bedescribed below.

Front and rear cover plate housings 50 and 52 are formed to mate withcorresponding end surfaces of the body housing 10 and the various thrustplate bushings, as shown, and a plurality of studs 54 extend throughopenings 56 in body housing 10 and threadedly engage cover housing 50.Recessed chambers 58 and 60 are formed in cover plate 52 adjacent theends of the shaft members and are connected by a passage 62 for ventingleakage fluid which passes bearings 18 and 24 to the inlet of the pumpby way of a passage 62 in shaft 16, a chamber 64 formed in cover housing50, a passage 66 in the cover housing, and a passage 68 which may beconnected to the inlet conduit 70 of the pump, while leakage fluid whichpasses bearing 26 flows along the shaft 22 and is vented to the inletconduit by way of passages 66 and 68.

Shaft sealing means 72 is located in an enlarged chamber 74 of coverhousing 50 between a seal retainer member 76, the shaft 22, and aportion of the cover housing. A snap ring 78 locates seal retainer 76 inchamber 74. The pump body and cover housing portions are pressure fluidsealed in operation by means of O-rings 80 and 82 which are located inthe body housing circumferentially outwardly of gear chamber 44. Adischarge conduit 84 is located in the body housing and opens into gearchamber 44 at the discharge side of the gears.

A plurality of axially extending passages extend inwardly of the bodyand rear cover housings from the mating surfaces 92 of said housings,and are vented at their one ends to preselected portions of the gearchamber adjacent the pockets of the gears and at their other ends to aplurality of chambers 94 which are formed in cover plate 52 insymmetrical relation to the gear chamber opening formed in body housing10, as best shown in FIG. 2. A piston element 96 is located in eachchamber 94 and responds to pressure fluid vented to the respectivechambers from the localized areas in the gear chamber to which thepassages 90 are connected. An O-ring 98 is located in cover plate 52 incircumferential relation to each passage 90 in order to prevent leakagethrough the mating housing surfaces 92. The inner ends of pistonelements 96 abut with the outer end of thrust plate bushings 28 and 32and impose a force thereon which acts through the various thrust platebushings and wear plates 40 and 42 to seal the side faces of the gearswith a force which is always proportional to the fluid pressure existentin the axially opposed localized area of the gear chamber 44. Inasmuchas the pressure in different localized areas of the gear chamber mayvary widely during operation as a function of operating parameters suchas pump r.p.m., fluid viscosity, cavitation, the volume of air entrainedin the fluid being pumped, and others, it will be apparent to personsskilled in the art that to the extent that piston elements 96 ofpredetermined area are properly located in relation to the outer end ofthe thrust plate bushings 28 and 32 and are properly vented todiflFerent localized areas in the gear chamber, the sealing forceimposed on the thrust plate bushings and wear plates by the plurality ofpiston elements will always vary in accordance with the particular.pressure gradient condition existing in the gear chamber of the pumpirrespective of variations in those factors which affect the pressuregradient, all as discussed in detail in my aforementioned patent.

In the present embodiment, for example, it will be noted (see FIG. 2)that the passage 90 which is located in inlet conduit 70 suppliesinletpressure fluid to. the three chambers 94 which are adjacent the inletconduit, whereas the passage 90 which is located adjacent the dischargeconduit 84 provides discharge pressure fluid to three chambers 94 whichare located adjacent the discharge conduit, and each of the other threepassages 90 located peripherally of the upper and lower gear chambersprovide pressure fluid from adjacent each respective area of the gearchamber to one or more chambers 94. It should be understood that inletpressure fluid is vented to those portions of the ends of bushings 28and 32 not in abutment with the piston elements 96; i.e., the area ofthe bushing ends surrounding the various piston elements.

Referring now to FIG. 3, the pump structure may be the same as describedwith reference to FIGS. 1 and 2, except that the distribution of pistonchambers and elements in the cover plate 52 is modified to provide theconfiguration shown in the cover plate 100. Openings 52 for receivingstuds 54 are the same as in FIGS. 1 and 2. Three piston chambers 102 arelocated adjacent the dis charge portion of the gear chamber and arevented by way of passages 104 to the pressure fluid in the dischargeconduit in a manner similar to that shown in FIG. 2. Upper and lowerpiston chambers 106 are located near the upper and lower portions of thegear chamber and are vented to the axially adjacent fluid pressures inthe chamber by way of passages 108, whereas chambers 110 are locatedsomewhat towards the inlet side of the pump from the vertical axisthereof and are vented to the axially adjacent portions of the gearchamber by passages 112. The remaining area of the cover plate 100disposed axially adjacent the gear chamber which is not abutted by thepiston elements 96, which are, of course, adapted to be located in thevarious piston chambers shown in FIG. 3, is vented to pump inletpressure. Thus, by somewhat less complex and lower cost pump structurethan that of FIGS. 1 and 2, an approximation of that force required toproperly seal the side faces of the gears by way of the various thrustplate bushings and wear plates is achieved under varying conditions ofpressure gradient in the gear chamber. It will be observed that theentire portions of the bushings 28 and 32 which lie axially adjacent theinlet'side of the pump are subjected to inlet pressure, but that theprevious requiremnt in the prior art for masking off the said area ofthe thrust plate by means such as is disclosed in my above-mentionedpatent in order to prevent excessive differential pressures actingadjacent the inlet side of the pump to seal the gear side faces, hasbeen eliminated.

In FIG. 4 I disclose in partial view a modification of the structureshown in FIG. 1 in which similar parts are similarly numbered, the onlysignificant difference being a simplification of the structure of thepassage means for venting the gear chamber to the piston chambers byproviding a straight drilled, axially extending passage 116 whichextends through the piston element 118, which is preloaded by a spring120 and has an O-ring 122 located in the piston element surrounding thepassage 116 to prevent leakage through the mating surfaces 92 of thehousing portions 10 and 52. The location of the piston elements 118 maybe in accordance with the embodiments shown in either FIGS. 2 or 3, oras shown in FIG. 5, to be described.

Referring to FIG. 5, the cover plate 130 is substantially the same asthe. cover plate 52- described in conjunction with FIGS. 1 and 2,including the distribution of piston chambers 94. However, in FIG. 5 thepassage construction 116, as described with regard to FIG. 4, isutilized for facilitating maximum accuracy in the response of the pistonelements operable in chambers 94 in respect of possible variations inpressure as between the, nine different gear vented chambers 94 in boththe upper and lower gear chamber portions. That is, each of the chambers94 in FIG. 5 is individually vented by means of a straight drilledpassage 116 which connects a different portion of the gear chamber ineach instance to the respective piston chamber. Consequently, the mostaccurate compensation for variations in pressure gradient under varyingcondition of pump operation may be obtained in the use of the FIG. 5embodiment, wherein every circumferential portion of each of the upperand lower gear chambers is vented individually to the adjacentcompensating piston chamber, so that collectively the piston elementsexert a total gradient compensated thrust of the thrust plate bushingsand wear plates which varies at all times in direct proportion to thefluid pressure existing in each of the axially adjacent gear chamberareas.

O-rings 98 in FIG. 3 correspond to the similarly numbered O-rings inFIG. 1, and O-rings 122 in FIG; 5 correspond to the similarly numberedO-ring in FIG. 4. In the embodiments of FIGS. 1, 2 and 5 it will benoted that the symmetry of distribution of the piston elementsfacilitates a ready solution to the problem of providing a reversiblepump by the use of check valves to reverse the inlet and dischargeconduit connections, as may be required in operation.

From the foregoing, it is believed that those familiar with the art willreadily recognize and appreciatethe novel concepts and features of thepresent invention. Also, while the invention has been described inrelation to only a few embodiments, variations, changes andsubstitutions of equivalents will present themselves to persons skilledin the art, and may be made without necessarily departing from the scopeand principles vof the invention. It will be appreciated that althoughthe invention has been described herein with particular emphasis on itsapplication to intermeshing gear type pumps,-

the principles of the invention are as readily applicable tointermeshing gear type motors. As a result, it is not my intention to belimited to any particular form of the invention herein illustrated anddescribed except as may appear in the claims appended.

I claim:

1. In a gear pump or motor, a gear body housing containing a pair ofintermeshing gears, axially movable thrust plate means mounted on atleast one side of the gears and having a remote abutment surface and asealing surface for sealing the adjacent side faces of the gears, aninlet leading to and outlet leading from said body housing, a coverhousing secured to said body housing at one end thereof, a plurality ofpiston chambers in the .cover housing located in predetermined spacedrelation, a plurality of corresponding piston elements in said chainshers movable axially of the pump into abutment with said remote surfaceof the thrust plate means, the parting planar surface between said coverand body housings being substantially coincident with the one ends ofsaid piston chambers, passage means connecting the other ends of saidpiston chambers to a plurality of peripheral gear chamber areas whichinclude gear chamber areas intermediate the inlet and dischargeconduits, said passage means extending directly through the thrust platemeans and throug each piston element in the cover housing to vent thesaid other ends of the piston chambers to the respective gear areas,said plurality of piston elements being adapted to act in concert toimpose upon the thrust plate means variably axially directed forces forsealing the adjacent side faces of the gears as a function of variationsin fluid pressure existent between the plurality of connections of thepiston chambers to the gear chambers, the area of said remote surf-aceof said thrust plate means which is not engaged by said piston elementsbeing vented to a gear chamber pressure less than discharge pressure.

2. A pump or motor as claimed in claim 1 wherein sealing means surroundseach of said passage means at the connection thereof at the matingsurfaces of said body and cover housings.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS3/1957 Great Britain.

DONLEY J. STOCKING, Primary Examiner.

WI'LBUR I. GOODLIN, Examiner.

1. IN A GEAR PUMP OR MOTOR, A GEAR BODY HOUSING CONTAINING A PAIR OF INTERMESHING GEARS, AXIALLY MOVABLE THRUST PLATE MEANS MOUNTED ON AT LEAST ONE SIDE OF THE GEARS AND HAVING A REMOTE ABUTMENT SURFACE AND A SEALING SURFACE FOR SEALING THE ADJACENT SIDE FACES OF THE GEARS AN INLET LEADING TO AND OUTLET LEADING FROM SAID BODY HOUSING, A COVER HOUSING SECURED TO SAID BODY HOUSING AT ONE END THEREOF, A PLURALITY OF PISTON CHAMBERS IN THE COVER HOUSING LOCATED IN PREDETERMINED SPACED RELATION, A PLURALITY OF CORRESPONDING PISTON ELEMENTS IN SAID CHAMBERS MOVABLE AXIALLY OF THE PUMP INTO ABUTMENT WITH SAID REMOTE SURFACE OF THE THRUST PLATE MEANS, THE PARTING PLANAR SURFACE BETWEEN SAID COVER AND BODY HOUSINGS BEING SUBSTANTIALLY COINCIDENT WITH THE ONE ENDS OF SAID PISTON CHAMBERS, PASSAGE MEANS CONNECTING THE OTHER ENDS OF SAID PISTON CHAMBERS TO A PLURALITY OF PERIPHERAL GEAR CHAMBER AREAS WHICH INCLUDE GEAR CHAMBER AREAS INTERMEDIATE THE INLET AND DISCHARGE CONDUITS, SAID PASSAGE MEANS EXTENDING DIRECTLY THROUGH THE THRUST PLATE MEANS AND THROUGH EACH PISTON ELEMENT IN THE COVER HOUSING TO VENT THE SAID OTHER ENDS OF THE PISTON CHAMBERS TO THE RESPECTIVE GEAR AREAS, SAID PLURALITY OF PISTON ELEMENTS BEING ADAPTED TO ACT IN CONCERT TO IMPOSE UPON THE THRUST PLATE MEANS VARIABLY AXIALLY DIRECTED FORCES FOR SEALING THE ADJACENT SIDES FACES OF THE GEARS AS A FUNCTION OF VARIATIONS IN FLUID PRESSURE EXISTENT BETWEEN THE PLURALITY OF CONNECTIONS OF THE PISTON CHAMBERS TO THE GEAR CHAMBERS, THE AREA OF SAID REMOTE SURFACE OF SAID THRUST PLATE MEANS WHICH IS NOT ENGAGED BY SAID PISTON ELEMENTS BEING VENTED TO A GEAR CHAMBER PRESSURE LESS THAN DISCHARGE PRESSURE. 